Various printing methods that can be used in rotary printing machines are known. One such printing method is inkjet printing. In this method, individual droplets of printing ink are ejected from nozzles in print heads and transferred to a printing material so as to produce a printed image on the printing material. By controlling a plurality of nozzles individually, different printed images can be produced. No set printing forme is used, thus each individual printed product can be designed separately. This allows personalized printed products to be produced and/or, since no printing forms are used, allows small print runs of printed products to be produced at low cost.
The precise alignment of a printed image on the front and back sides of printing material imprinted on both sides is referred to as register (DIN 16500-2). In multicolor printing, when individual printed images of different colors are combined in precise alignment to form a single image, this is referred to as color registration (DIN 16500-2). In inkjet printing, suitable measures must also be implemented to maintain color registration and/or register.
From EP 2 202 081 A1 and from JP 2003-063737 A, printing machines are known, in which the printing machine comprises a first printing unit and a dryer, the first printing unit having a central cylinder with an integral drive motor dedicated to the first central cylinder, and at least one inkjet print head, which is aligned toward an outer cylinder surface of the first central cylinder.
From EP 1 155 987 B1, a roll unwinding device for a web-fed rotary printing machine is known, wherein the roll unwinding device has at least one roll holding device and at least one drive motor, connected to the at least one roll holding device via at least one torque transfer device, and wherein the roll unwinding device has at least one common support or support frame, which has two supporting arms and/or on which two supporting arms are disposed, and which is arranged so as to pivot about a pivot axis relative to a stationary frame of the roll unwinding device.
From US 2008/094443 A1 a printing machine is known which comprises at least one first printing unit, wherein the at least one first printing unit has at least one inkjet print head, at least one first central printing cylinder and an integral first drive motor, dedicated to the at least one first central printing cylinder, and wherein a transport path of a printing material web through the printing machine has at least one first section and one second section, each of which is delimited by contact points of the printing material web with motor-driven rotating bodies, and wherein at least the first section has at least one first dedicated measuring device for measuring a web tension of the printing material web in the first section, and wherein at least the second section has at least one second dedicated measuring device for measuring the web tension of the printing material web in the second section.
From US 2002/166470 A1, a printing machine is known which comprises at least one first printing unit, wherein the at least one first printing unit has at least one inkjet print head, at least one first central printing cylinder and an integral first drive motor, dedicated to the at least one first central printing cylinder, and wherein a transport path of a printing material web through the printing machine has at least one first section and one second section, each of which is delimited by contact points of the printing material web with motor-driven rotating bodies.
From EP 2 161 136 A1, a printing machine is known, said printing machine having at least one first printing unit, wherein the at least one first printing unit has at least one inkjet print head. Only a single section of a printing material which is delimited by contact points of the printing material web with motor-driven rotating bodies is specified. The optionally specified measuring devices on transport rolls are all located within this section.
From US 2011/063389 A1, a printing machine having a first printing unit, an inkjet print head is known, wherein a transport path of a printing material web through the printing machine has at least one first section and one second section, each of which is delimited by contact points of the printing material web with motor-driven rotating bodies.
It is also known to employ the inkjet printing method for imprinting textile printing materials. Textile printing materials in this context are understood particularly as those materials that are listed in DIN 60000 (January 1969). In contrast to printing materials such as paper or metal, textile printing materials are relatively unstable in shape. For instance, textile materials frequently are more or less stretchable, wherein when the material is stretched in one direction, it usually contracts in another direction, for example, oriented orthogonally to the first direction. For this reason, to ensure a true-to-register imprinting of textile printing materials, not only must the printing material be properly positioned, a stable shape of the printing material must also be maintained at least during the printing process.